Back to the guitar — and just one string at a time. Because a single string is a straight chromatic line, the major-scale formula becomes one simple rule: move two frets to the next degree, except one fret between 3→4 and 7→1. You'll play the scale up and down any string while always tracking which scale degree your index finger is on (use only that finger, and freeze the root as a drone). Why one string? It sharpens your melodic sense, survives any tuning, and trains the scale-degree awareness everything later in the course depends on.